Mass spectrometer

Abstract

A sample S is irradiated with a two-dimensionally spread ray of laser light to simultaneously ionize substances within a two-dimensional area on the sample. The resultant ions are mass-separated by a TOF mass separator 4 without changing the interrelationship of the emission points of the ions. The separated ions are then directed to a two-dimensional detector section 7 through a deflection electric field created by deflection electrodes 61 and 62 . The two-dimensional detector section 7 consists of a plurality of detection units 7 a arranged in parallel, each unit including an MCP 8 a , fluorescent plate 9 a and two-dimensional array detector 10 a . The magnitude of deflecting the flight path of the ions by the deflection electric field is changed in a stepwise manner with the lapse of time from the generation of the ions so that a plurality of mass analysis images are sequentially projected on each detection unit 7 . When the mass analysis image shifts from one detection unit to another, the data acquisition operation by the two-dimensional array detector in the previous detection unit is discontinued. As a result, a predetermined number of the latest images are held inside the detector. Thus, the measurement time can be extended to widen the measurable mass-to-charge ratio range, while ensuring a high mass resolution.

1. A mass spectrometer, comprising:
 a) an ionizer for simultaneously ionizing components present within a predetermined two-dimensional area on a sample; 
 b) a mass separator for separating ions, generated by the ionizer, in such a manner that the ions will be emitted at different points in time according to their mass-to-charge ratio while maintaining a two-dimensional relative positional relationship with which the ions have been generated; 
 c) a two-dimensional detector including multiple pairs of converters and two-dimensional array detectors, 
 each converter receiving the ions separated by the mass separator and converting each ion into a photon or electron whose amount corresponds to that of the ion, while maintaining the two-dimensional relative positional relationship with which the ions have been generated, 
 each two-dimensional array detector consisting of an in-situ storage image sensor having a detector section and a memory section, the detector section including two-dimensionally arrayed micro detection elements each detecting the photon or electron produced by the converter and outputting a corresponding electric signal, the memory section being capable of individually holding electric signals produced by each micro detection element for a predetermined number of frames, 
 the multiple pairs of converters and two-dimensional array detectors being arranged in parallel along an extending direction of the detector section; and 
 d) an ion deflector located in a space between an ion emission port of the mass separator and the converters, for creating an electric field and/or magnetic field producing a force for deflecting a flight path of an ion passing through the space, 
 wherein a magnitude of deflecting the flight path with the ion deflector is changed so that an ion passing through the ion deflector at a different point in time will be detected by a different pair of the converter and the two-dimensional array detector in the two-dimensional detector. 
 
     
     
       2. The mass spectrometer according to  claim 1 , wherein the mass separator is a time-of-flight mass analyzer. 
     
     
       3. The mass spectrometer according to  claim 1 , further comprising a controller for controlling an operation of storing electric signals in the memory section in each two-dimensional array detector, wherein the controller controls each of the multiple two-dimensional array detectors so that the aforementioned operation will be synchronized with a timing at which an ion reaches the converter for the two-dimensional array detector concerned. 
     
     
       4. The mass spectrometer according to  claim 1 , wherein the ion deflector includes one or more pairs of deflection electrodes facing one another across the space which the ions pass through and a voltage applier for applying a voltage to the deflection electrodes, and the voltage can be changed so as to change the magnitude of deflection of the flight path of the ions. 
     
     
       5. The mass spectrometer according to  claim 1 , wherein:
 the ion deflector includes a pair of magnetic poles for generating a magnetic field, the magnetic poles facing each other across a space which the ions pass through; and 
 the magnitude of deflection of the flight path changes with a change in the mass-to-charge ratio of ions passing through the magnetic field. 
 
     
     
       6. The mass spectrometer according to  claim 1 , wherein the two-dimensional array detector is an in-situ storage image sensor having the detector section formed by the two-dimensionally arrayed micro detection elements performing photoelectric conversion. 
     
     
       7. The mass spectrometer according to  claim 1 , wherein the two-dimensional array detector is a reverse-side type in-situ storage image sensor in which each micro detection element captures and detects an electron impinging on a detection surface located on a side opposite to a side where the detector section is formed.